1. Field of the Invention
This invention relates to a suspension for a disc drive contained in an information processor, such as a personal computer.
2. Description of the Related Art
A hard disc drive (HDD) for recording and reading information to and from a rotating magnetic disc, magneto-optical disc, etc. has a carriage that can turn around a shaft. A positioning motor turns the carriage around the shaft. The carriage comprises an actuator arm, a suspension on the distal end portion of the arm, a head portion including a slider on the suspension, etc.
If the disc rotates, the slider on the distal end portion of the suspension slightly lifts above the surface of the disc, and an air bearing is formed between the disc and the slider. This suspension comprises a base plate, a load beam, a flexure, etc.
A suspension for disc drive described in Jpn. Pat. Appln. KOKAI Publication No. 2001-155458 comprises a base portion including a base plate, a load beam formed independently of the base portion, and a hinge member that connects the load beam and the base portion. A flexible portion (region between the load beam and the base portion) of the hinge member can bend in its thickness direction. This flexible portion serves as a hinge portion.
In some cases, a wired flexure may be located along the load beam. A magnetic head that includes a slider is mounted on the front end portion of the flexure. The wired flexure extends from the load beam toward the base portion via the hinge portion.
If the wired flexure passes over the hinge member when it is located overlapping the load beam and the base portion, it is inevitably deformed in its thickness direction by a margin corresponding to the thickness of the hinge member. Thus, the wired flexure ceases to be flat. Possibly, therefore, bending stress may develop in the wired flexure and influence the properties of the suspension.
In order to prevent generation of bending stress in the wired flexure, a layout may be proposed such that the flexure detours around the hinge portion. With this arrangement, the wired flexure can be made flat. Since the wired flexure passes on one side of the hinge portion in this case, however, the weight distribution in the region near the hinge portion is asymmetric. This may possibly influence the vibration characteristics of the suspension.
The width of the conventional hinge member is equal to that of the base plate, and the other regions of the hinge member than the flexible portion overlap the load beam and the base portion. If the conventional hinge member is used, therefore, it increases the mass of the suspension. In order to shorten the seek time of a disc drive, the mass of the suspension should be lessened. It is difficult, however, to shorten the seek time if the mass of the suspension increases owing to the use of the conventional hinge member that has a large mass.